Carrier HS070-160 manual T21

LEAVING WATER

SUCTION ,----CONNECTION

(T58T6)

\

COOLER TUBE

INLET

CONNECTION

THERMISTOR..

ENTERING COOLER

WATER SENSOR

(T21

Fig. 4 - Cooler Sensor Locations

Bau’ The~~isfor ~ Thermistors mis-located or out of calibration.

Code 68 and 69, Low Suction Superheat ~‘-- if the follow- ing logic is satisfied, then all the compressors on the circuit will be stopped.

Suction superheat is equal to 0°F (OOC) or the satu- rated suction is greater than 58 F (14.4 C) and either condition has been true for more than 5 minutes.

Possible causes for this failure are a stuck electronic expansion valve or thermistors mis-located or out of calibration.

To reset, use the manual reset method.

Code 71 to 81, Thermistor Failure ~~~ If the measured temperature of a thermistor is less than -60 F (-51 C) (363,000 ohms) or greater than 240 F (116 C) (2 16 ohms), the appropriate sensor error code will be displayed and the unit will be stopped. The thermistor failures will automatically reset. The following is a summary of possible causes.

Thermistor Failure - A shorted or open circuit ther- mistor will cause the failure.

Wiving Failure - A shorted or open circuit will cause the failure.

P~oc~essnr Module Fczilure ~ If the circuitry in the pro- cessor module fails, the error could occur.

NOTE: The reset thermistor is an optional thermistor and is only used with outside or space temperature reset. It will only be read by the processor if the unit is con- figured for outside or space temperature reset.

The absence of a thermistor failure does not necessarily mean that a thermistor is accurate . To determine

accuracy, the reading must be compared with a measure- ment of the actual temperature to which the thermistor

probe is exposed.

Quick Test - The Quick Test feature allows the service technician to individually test all the inputs and outputs of the control system.

The test function operates the Quick Test diagnostic program. When the unit is in STANDBY mode, the test subfunctions will energize the solenoid valves, unloaders, electronic expansion valves and compressors. The solenoids and unloaders will energize for 3 minutes. The electronic expansion valve will travel to fully open in one test and to fully closed in the next. The compressors will energize for 10 seconds. The subfunctions are explained below. Refer to Table 6 for all the elements in the subfunctions.

NOTE: The Quick Test energizes the alarm light and alarm relay. They will remain energized as long as the unit is in Quick Test.

To reach a particular test, enter its subfunction number

and then scroll to the desired test with the + key. A 0

test can be terminated by pressing + . Pressing +

c lEl after a test has started will advance the system to the next test, whether the current one is operating or has timed out. Once in the next step, you may start the test

by pressing ENm or advance past it by pressing h .

c lc l While the unit is in Quick Test, you may access another display or function by depressing the appropriate keys; however, the unit will remain in the Quick Test func-

tion until T;;iH is entered, or, if the keyboard is

not used for 10 minutes, the unit will automatically leave the Quick Test function. See the following example:

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